Hand tool



Aug- 4, 1953 E. c. NEAL 2,647,312

HAND TOOL Filed May l2, 1949 i Patented Aug. 4, 1953 UNITED STATES PATENT OFFICE HAND 'rooL Ernest C. Neal, Chicago, Ill., assigner of one-half to Elmer Brandell, Chicago, Ill.

Application May 1,2, 1949, serial No. 92,896

s claims. (o1. :io-189) The present invention relates ingeneral to power multiplying lever systems, and has more particular reference to an improved lever system especially well suited for incorporation in cutters, pliers, nippers, shears andv the like; the present'invention being'particularly well adapted for use in providing powerful hand tools of relatively small size and convenient usage..

An important object of this invention is to provide compact, inexpensive, simple and eilicient mechanism having closable jaws, wherein the application of relatively little force on the instrument will exert relatively powerful jaw closing forces. f

Another important object isk to provide a lever mechanism of the character mentioned, which increases its power multiplying effect during its operating stroke; a further object being to provide a lever system in which the power multiplying effect increases to a maximum during the initial stages of the operating stroke of thesys'- tem, whereby, when applied as a cutter, a maxi# mum cutting-effect of the cutter jaws may 'b e attained during, preferably at the medial `portions of, the operating stroke of the device.

Another important `object is to provide a compound lever system providing for the movement of a Working lever, about its fulcrum, by the application of force, to a portion of the working lever, through the medium of an auxiliary lever member adapted to apply force to a bearing portion of the working lever, at progressively increasing distance from the fulcrum thereof, during the working stroke of the system; a further object being to form such bearingportion'as' a' cam surface, along which a cam following portion of the auxiliary lever is adapted to during'the operation of the system.

' Another important object is to provide `the auxiliary lever with a pair of cam following por.- tion's adapted successively to bear upon andtravel along the cam surface of the working lever during the working-stroke of the apparatus. n

Another important object is to utilize roller means on the auxiliary lever forcamming purposes with the work lever.

Another important object is to so form the levers and locate the pivots thereof, and to shape mOVe the cam surface of the working lever, so'as to de# termine the angle of attack of the cam following' operating stroke of the apparatus; a still further:

progressively decreasing the angle of attack dur-A ing the operating stroke.

Another important object resides in controlling power multiplication in a compound lever system by forming the cam surface of the work lever as a curved surface of desired configuration to obtain a desired variant power multiplying rati during the working stroke of the system.

Another important object resides in providing" an unusually powerful cutter or pliers for hand operation, and embodying the novel compound leverage system of the present invention.'

The foregoing and numerous other importantv objects, advantages, and inherent functions of the invention will become apparent'as the same is more fully understood from the following description, which, taken iny connection with the` accompanying drawings, discloses preferred embodiments of the invention.

Referring to the drawings: v y

Fig. 1 is a sectional view. taken longitudinally through a cutter device embodying the present invention, the parts being shown in relatively] open position, as at the commencement of a cuttingstroke;

Fig. 2 is a fragmentary view of ther device, shown in Fig. 1, illustrating the parts in partially closed position, as at a medial position during the operating stroke of the device;

Fig. 3 is a fragmentary view, similar to Fig'. 2,v showing the parts inF fully closed position,`asy atv the end'of the operating stroke of the device;l

Fig. 4 is a sectional view taken substantially along the line 4-'4 in Fig. l; Fig. 5 is a. sectional view taken'l substantially along the line 5 5 in Fig. 2;

Fig. 6 is a sectional view taken substantiallyk along the line 6--6 in Fig. 3; and

Fig. 7 is a fragmentary view, similar to Figs. 2 and 3, illustrating a modified form ofthe in-2 vention. y i i l To illustrate the invention, the drawings show a cutting device Il particularly adapted'formanual operation, the device specifically shown being a wire or rod cutter, although itwill be apparent that the` invention is not necessarily limited tof the specific use to which it may be put, the vsame y I2, which may conveniently be formed as a sheet metal stamping. At one end the frame is formed to provide a jaw I3. This jaw may, of course, be formed in any suitable, preferred or convenient fashion, but, as shown, it comprises a block I4, preferably of hardened cutting material such as tool steel, the block being formed to desired shape to provide a cutting edge I and secured in the main frame I2 in any suitable fashion, as by welding or riveting the same in place. Adjacent the block I4 the main frame provides a mounting for a pivot pin I5, secured at its opposite ends, as in a pair of spaced apart panel portions or wings I'I of the main frame.

The pin IB forms a fulcrum pivot fora lever member I3, which comprises the working lever of the system. This working lever extends between the panels I'l of the main frame, is pivoted on the pin I6, and formed at one end to provide` a jaw i9 in position to register and cooperate With the jaw I3 and to close on and to open with respect to said jaw, in response to relative angular movement of the lever it with respect to the main frame about the fulcrum pivot I6.

The levermember I8 may conveniently comprise a formed block of tool steel or other hard cutting material, and may be formed with a cutting edge in position to cooperate, in registering alinement, with the cutting edge i5 when the jaws are in the relativeiy `closed position shown in Fig. 3. On the side of the pivot I6 remote from the jaw i9', the lever member iS may be formed with a thrust surface 2i, and may be normally urged toward jaw open position on the fulcrum pivot I6 by biasing spring means 22, preferably comprising a helical tension spring, anchored at its opposite ends, respectively on the lever i8 and on the main frame I2 between the Wings or panels Il thereof'. This spring normally serves to yieldingly urge the lever I8 toward relatively open position on the main frame i2, as shown in Fig. l.

To close the Working lever I 3 against the inuence of the spring 22, a manually operable auxiliary lever 23 may be provided. This' lever may conveniently be mountedfor pivotal movement on and with respect to the main frame I2, as by means of a pivot pin 24 secured at its opposite ends in spaced apart extensions 25 of the panel portions H' of the main frame.

rIhe handle 23, like the main frame, may be formed of sheet metal and may provide journal means, such as the ears 2B, for pivotally mounting the auxiliary lever 23 on the pin '.M in position extending between'the panel portions H' of the main frame. On one side of the pivot 24 the lever 23 provides a handle, by means of which power may be applied thereto in order to turn the same upon the pivot 2,4 in the performance of the operating stroke of the lever system. To this, end, the main frame I2,at the end' thereof remote from the jaw I3, may beA formed to provide a handle 27, whereby to hold or anchor the main frame to facilitate the movement 'of the handle 23 during the operation of' the device. Preferably, the members 23 and 2t form cooperating handles that may be drawn together by the contraction of the hand of the operator of the device inl thev performance of the operating stroke.

The auxiliary lever 23 -is provided with bearing means for engagement with the thrust surface 2l of the Work lever I8, such thrust surface 2I providing a cam surface, and such bearing 4 means on the auxiliary lever preferably comprising a roller or rollers 28, 28. The rollers 28, 28 may conveniently be journaled on pins 29, 29 mounted at their opposite ends in extensions 30 of the lever 23. The roller means 28, 28 is positioned to engage and ride upon the cam surface 2I of the Work lever. The rollers thus form bearing .means for imparting thrust upon the thrust surface 2l of the working lever; and while it is entirely feasible to employ non-rotary or fixed bearing members on the auxiliary lever, it is preferable to employ roller means as shown to facilitate free movement of the bearing element or .elements along the thrust surface. It will be understood, however, that the invention is not necessarily restricted to the roller form of the bearing or thrust elements 28,4 28', specifically shown.

In moving from the fully open position, shown in Fig. l, during the operation of the device, closing movement of the auxiliary lever 23 will cause the roller 23 to move from its position of initial engagement with the surface 2l in a drection away from the fulcrum pivot I6 of the working lever, thereby increasing the leverage arm between said fulcrum pivot and the point of engagement of the roller 28 on the cam surface 2I. During the operating stroke of the mechanism, also, it will be noted that the angle of attack, or thrust of the roller 28 upon the surface 2i, takes place, in the illustrated embodiment, substantially at right angles to such surface.

This angle of attack, however, during the op.

merely necessary to provide suflicient length inthe lever I.8 so that the roller 28 will not. leave the cam surface 2I during the operating stroke-- of the device.

As shown, however, an exceedingly compact and effective apparatusmay be provided by form-v ing the Working lever I8 so that the roller 28 will reach the fulcrum pivot remote end of the cam surface 2I and become disengaged therefrom. during and prior to the completion of the operating stroke. In such arrangement, the roller 28" is so positioned on. the lever as to come into engagement with the cam surface 2l as the roller 28 becomes disengaged from such surface, so that the roller 28 may transfer power from the auxiliary lever 23 to the work lever I8 during the terminal portions of the operating stroke of the device. In performing its function',4 the rollerv28, after engaging the camsurface 2.I,.Will roll thereon in a direction away from. the fulcrumy pivot I6.. thereby increasing the powermultiplying Aeiiect during the course of its operating movement on: the cam surface. During the course of such^ operating movement of the roller 28', the angleV of attack of the auxiliary lever on the work. lever decreases, thereby increasing the wedging effect,` in fashion previously noted in connectiony with, the operation of the roller 28.

It will be seen from the foregoing that, Where a plurality of successively operating rollers 2U.'

28'-.are.utilized tot transfer power from the auxiliary to theworking lever, power multiplication is initially accomplished during the working .strokeyby the action of the roller 28, power multiplication reaching a maximum as said rolle r reaches the end of the cam surface ZI.l Maximum power at the jaws I3, I9, in response toa given 'force applied on the auxiliary lever 23, is thus exerted during the medial stages of the operating stroke of the device. This result is particularly desirable where the cutting of rods is involved, since the maximum resistance to cutting, in rods, is encountered midway of the cutting stroke. After such maximum cutting resistance point is reached, in the cutting of rods, resistance to cutting falls off rapidly so that the required force for completing the cut may be materially reduced. This is amply supplied in the present invention by the roller 28.

The multiple roller construction not only allows the use of a shorter working lever 28 at its cam surface end, thereby affording compact structure, but also provides a cutter of maximum eiiiciency for the cutting of relatively large diameter rods, in which the cutting action is initially accomplished by the roller 28, and finally by the roller 28'. The structure also affords maximum cutting efficiency where small section rods of tough material are required to be severed. With such small section rods the roller 28 provides maximum power multiplication toward the medial and end portions of its operating stroke.

As shown more particularly in Fig. 7, the cam surface 2|, whether single or multiple roller structure is involved, may be curved in order to obtain a desired power multiplication at any stage during the operating stroke of the device. Where the cam surface is curved, as shown in Fig. 7, power multiplication will increase at a rate different from that at which it increases wherethe cam surface 2I is substantially at, as shown in Figs. 1-3. This characteristic may be advantageously utilized where it is desired to accomplish particular relative multiplication during selected portions of the operating stroke.

In order to provide a stop for limiting the opening movement of the device, under the influence of the biasing spring 22, the main frame I2 may be provided with an offset shoulder 3| in position to cooperatively engage with an extension on the auxiliary lever 23, such extension in the illustrated embodiment comprising the roller 28'.

It is thought that the invention and its numerous attendant advantages will be fully understood from the foregoing description, and it is obvious that numerous changes may be made in the form, construction and arrangement of the several parts without departing from the spirit or scope of the invention, or sacrificing any of its attendant advantages, the forms herein disclosed being preferred embodiments for the purpose of illustrating the invention.

The invention is hereby claimed as follows:

1. A hand tool comprising a main frame forming a handle portion at one end and a jaw portion at the other, a Work lever forming a cooperating jaw. means forming a fulcrum pivot for said work lever on said frame adjacent the jaw portion, an operating lever forming a handle, a mounting pivot on said frame for mounting said operating lever for angular movement toward said handle portion in the performance of a .jaw closing stroke of the operating lever, said work lever having a cam surface thereon extending outwardly of said-[fulcrum pivot toward said mounting pivot, and a pair of spaced apartbearing members on said operating leverin position, between said fulcrum andmountingpivots, to successively engage. said cam 4surface in a direction progressively away'from said fulcrum .pivot during the jaw closing stroke of the operating lever', wherebyweachf. of said bearing members during its engagement with the cam surface exerts a progressively increasing force on` the cam surface during its movement therealong.

2. A hand tool comprising a main frame forming a handle portion at one end and a jaw portion at the other, a work lever forming a cooperating jaw, means forming a fulcrum pivot for said work lever on said frame adjacent the jaw portion, an operating lever forming a handle. a mounting pivot on said frame for mounting said operating lever for angular movement toward said handle portion in the performance of a jaw closing stroke of the operating lever, said work lever having a cam surface thereon extending substantially radially outwardly of said fulcrum pivot toward said mounting pivot, and a pair of spaced apart bearing members on said operating lever in position, between said fulcrum and mounting pivots, to successively engage said cam surface in a direction progressively away from said fulcrum pivot during the jaw closing stroke of the operating lever, whereby each of said bearing members during its engagement with the cam surface exerts a progressively increasing force on the cam surface during its movement therealong.

3. A hand tool comprising a main frame forming a handle portion at one end and a jaw portion at the other, a work lever forming a cooperating jaw, means forming a fulcrum pivot for said work lever on said frame adjacent the jaw portion, an operating lever forming a handle, a mounting pivot on said frame for mounting said operating lever for angular movement t0- ward said handle portion in the performance of a jaw closing stroke of the operating lever, said work lever having a cam surface thereon extending outwardly of said fulcrum pivot toward said mounting pivot, and a pair of spaced apart bearing members on said operating lever, including a main bearing member and an auxiliary bearing member spaced on said operating lever further from said mounting pivot than the main member, said members being disposed in position between said fulcrum and mounting pivots to successively engage said cam surface in a direction progressively away from said fulcrum pivot during the jaw closing stroke of the operating lever, whereby each of said bearing members during its engagement with the cam surface exerts a progressively increasing force on the cam surface during its movement therealong, said auxiliary bearing member being disposed on said operating lever in position to engage and commence its operating movement on said cam surf-ace as the main bearing member concludes its operating movement on said cam member.

4. A hand tool,.as set forth in claim 3, wherein said members are disposed in position each to initially attack the cam surface at substantial angles and thereafter at progressively decreasing angles during the movement thereof along the cam surface.

5. A hand tool, as set forth in claim 3, wherein the main bearing member is disposed in position initially to attack the cam surface in a direction substantially normal thereto and thereafterat 7 progressively decivseasurigv angles @f met during the jaw chasing movement ef the peatifg lever, the auxiliary member being positioned te' initially attack the cam surface at a Substantial angle and thereafter at progressively decreasing angles d during the movement thereof along the @am su= face.

Refeifedes Cited in the leof this patent NITE'D STATES PA'N TS Number 908,790 1,435,131 1,453,354 2,385,835

Name ate. Mallam Q -ehh Jah.' 5, 1905 Jaeebson .u u- Nov. '1, 1922 Parker L May i, LQS Naai eeemeemg ct. 2, 1945 

